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Development of collimator insert for linac based stereotactic irradiation.
I R Singh1, S Brindha, B P Ravindran
1Department of Radiotherapy, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
Physics in Medicine and Biology
|October 26, 1999
Summary
Researchers developed custom collimator inserts using Cerrobend, achieving dosimetry accuracy within ±2.4% for clinical applications. This cost-effective method ensures suitability for various field sizes in radiation therapy.
Area of Science:
- Medical Physics
- Radiation Oncology
- Materials Science
Background:
- Commercially available collimator inserts can be expensive or unavailable.
- Accurate dosimetry is crucial for effective radiation therapy.
- Local development of medical devices can reduce costs and improve accessibility.
Purpose of the Study:
- To develop and validate custom collimator inserts using low-melting alloy (Cerrobend).
- To compare dosimetry parameters (TMR, OAR, output factor) with commercial inserts.
- To ensure clinical suitability through rigorous acceptance and dose verification testing.
Main Methods:
- Fabrication of 15 mm collimator inserts using Cerrobend.
- Dosimetric comparison with commercial Radionics inserts.
- Performance of acceptance tests: concentricity, beam size, radiation leakage.
- Dose verification using thermoluminescent dosimeters (7LiF rods) and FBX chemical dosimeters in a phantom.
Main Results:
- Dosimetry parameters of developed inserts were comparable to commercial ones.
- Acceptance tests confirmed suitability for clinical use.
- Dose variations within +2.4% (7LiF) and -2.0% (FBX) were achieved during verification.
Conclusions:
- The developed Cerrobend collimator inserts are suitable for clinical use.
- The fabrication method is standardized and cost-effective.
- This facilitates the development of custom inserts for diverse field sizes in radiation therapy.